CAMEROON PAST GCE ORDINARY LEVEL COMPUTER …...May 05, 2019 · Name any three hardware devices...

CAMEROON PAST GCE ORDINARY LEVEL COMPUTER SCIENCE PAPER 2 QUESTIONS

& ANSWERS FROM 2016 – 2019

Compiled By:

GAMO NANA

Credits to:

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www.cameroongcerevision.com

www.thebigbrain.com

May 2020 Edition

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Table of Contents STRUCTURE OF THE EXAM...........................................................................................................

1. QUESTION SECTION ..............................................................................................................

1.1. JUNE 2019 ......................................................................................................................

1.2. JUNE 2018 ......................................................................................................................

1.3. JUNE 2017 ......................................................................................................................

1.4. JUNE 2016 ......................................................................................................................

2. ANSWER SECTION .................................................................................................................

2.1. JUNE 2019 ......................................................................................................................

2.2. JUNE 2018 ......................................................................................................................

2.3. JUNE 2017 ......................................................................................................................

2.4. JUNE 2016 ......................................................................................................................

SOME TIPS WHEN WRITING THE EXAM ......................................................................................

STRUCTURE OF THE EXAM Computer Science at the Ordinary level consist of 3 papers namely: Paper 1, 2 and 3.

Paper 2 accounts for 30% of the overall mark. It consists of 7 essay questions of which you

are required to answer 5.

This paper has duration of 2hrs.

This book would help you get familiar with the type of questions and will help you to tackle

the exam with ease.

Disclaimer: The answers provided here are not the official marking guide. They express a

personal point of view. Feel free to contribute or report a problem at

gamonana.wordpress.com/contact

You are free to reproduce and share this book without the author’s permission.

1

1. QUESTION SECTION

2

1.1. JUNE 2019

3

gcerevision.com

COM PITER SCIENCE 20595

CAMEROON GENERAL CERTIFICATE OF EDUCATION BOARD

General Certificate of Education Examination

ORDINARY LEVELJUNE 2019

Subject Title COMPUTER SCIENCEPaper No. 2Subject Code No. 0595

Two Hours

Answer any FIVE questions.All questions carry 20 marks each. For your guidance, the approximate mark for each part of a question is indicated inbrackets.You are reminded of the necessity for good English and orderly presentation in your answers.In calculations, you are advised to show all the steps in your working,giving your answer at each stage.

Calculators or Phones are NOT allowed.

Turn Over -00/0595/2/A/Q© 2019 CGCEB

b - C

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V1

Stale any two positive impacts in each case of C omputei Inlormation System on t IC

following areas:BankingManaging a School Libra17Commerce

(a)

(2 marks)(2 marks)(2 marks)

(i)(ii)(iii)

(b) Explain what you understand by the following:System SoftwareOperating SystemDevice driversUtility software.

(2 marks)(2 marks)(2 marks)(2 marks)

(i)(ii)(iii)(iv)

(c) (i) Give the difference between optical and magnetic storage devices in terms of the technology usedto store data. (4 marks)

(ii) By using diagrams only, show how the layout of the tracks and sectors on compact disc differ fromthose of a hard disk. (2 marks)

2 . (a) Stale DeMorgan’s Laws for a logic circuit with two inputs A and B

Given the logic circuit Figure I. Write down the logic expression for the output.

(4 mark)

(b)

A

B PR

C QD

Figure l

P in terms of inputs A and BQ in terms of inputs C and DR in terms of inputs A, B, C and D.

(0 (2 marks)(2 marks)(2 marks)

(ii)(iii)

(c) (i) What is ergonomics?(ii) Briefly describe any Three

organization.(2 marks)ways in which ergonomic design is applied in an(6 marks)

(d) Using binary arithmetic,evaluate 10000112- 11102Give the difference between

Intranet and extranet.The internet and World Wide Web (WWW)Browser and Search engine.Give two advantages and two disadvantages of usinusooi . .• •State any two social media platforms.

b h med,a »> a school.

(2 marks)(a)3.

(i)(ii) (2 murks)

(2 murks) *

(2 murks)

(4 murks)(2 murks)

(2 marks)(2 murks)

(2 murks)

(2 murks)

(iii)

(b) 0)(ii)

(c) (i) What is Computer Generation?State the(ii) main technology that character!nzes the 2nd and 3rd computer generations.

(d) (i) What is Green Computing?Name two ways by which i(ii)

'1 can be enhanced.

2019/0595/2/A

V -

Mb »»

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(a) Give the meaning of the following terms used in project management.Predecessor taskCritical pathSlack time

4.(2 marks)(2 marks)(2 marks)

( i )( ii )( iii )

A teacher intends to present a lecture to students in a hall using a computer application software.State the most appropriate Application Software that can be used. Give one reasonfor your choice.Name any three hardware devices thatfacilitate the teacher’s lecture in the hall.Name two other Application Software that can be used to prepare the lecture.

Give two differences between an impact printer and a non-impact printer.Give an example of each type of printer in c(i ).

(b)(i )

(2 marks)

(ii ) be used alongside the computer tocan(3 marks)(2 marks)(i)

(2 marks)(2 marks)

(c) ( i )( i i )

(d ) State the role of each of the following in relation to data transmission.( i ) Receiver( ii ) Transmitter( ii ) Protocol

(1 mark)(1 mark)(1 mark)

A Folder in a computer contains files with total si /e of 7 GB. In order to backup thefiles, a number of CDs of size 700 MB are provided.

What do you understand by file backup?Give two reasons for file backup.Convert 7GB to MBHow many CDs are required to backup all the files in the folder?

5. (a )

( 1 mark)(2 marks)(3 marks)(3 marks)

( i )( i i )( i i i )( is )

Write in full the abbreviation DBMSBriefly explain the following as used in DBMS:

RedundancyConsistencyNormalization

Differentiate between data verification and data validationBriefly explain why both data verification and data validation are necessary toensure the credibility of data in a database

( 1 mark)( b) ( i )( i i )


( i )(c) (2 marks)( ii )

(2 marks)

The technician of a computer laboratory in a school decides to replace a Proprietary Operating systemwith an Open Source Operating System. I le equally replaced the RAM chips with RAM of highercapacities and supplied power to each computers through a UPS.

Briefly explain the advantages of the three changes effected by the technician.Briefly explain what you understand by Free and Open Source Software.Write in full the abbreviation UPS to the computer system.Give two advantage of UPS to the computer system.Suggest other tw o changes that can improve the functioning of the computers

(a )6 .

(i) (6 marks)(3 marks)(1 marks)(2 marks)(2 marks)

( ii )( iii )( iv)(v)

Briefly explain the following:( i ) Multitasking and multiprocessing.

Software upgrading and updating,

( iii) Uploading and downloading.

( b)(2 marks)(2 marks)(2 marks)

( ii )

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7. (a) Briefly explain what you understand by:Algorithm

(ii) Pseudo codeFlow chart


(i)

(iii)

(b) Give the difference between:Source code and object code.Compiler and assembler.Declarative and procedural programming.

Briefly explain the roles of the Six (06) main components of an Information System.Describe briefly how school management can use an Information System to manageindiscipline in students.


(0(ii)(iii)

(6 marks)(c) (0(ii) (2 marks)

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1.2. JUNE 2018

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9


10


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12

1.3. JUNE 2017

13

Computer science Paper 2 (for more past questions visit http://gcerevision.com)

June 2017 Code: 0595 gcerevision.com

Instructions: answer any five questions (Two hours)

1. (a) briefly describe the following terms in relation to data security

(i) Data Encryption (2 marks)

(ii) Backup (2 marks)

(iii) Fire wall (2 marks)

(b) Briefly explain what is meant by data integrity (3 marks)

(c) state the difference between data verification and data validation (4 marks)

(d) (i) Briefly explain what you understand by computer simulation (2 marks)

(ii) state two advantages and two disadvantages of computer simulation (4 marks)

2. (a) Explain briefly the following data processing methods

(i) Batch processing (2 marks)

(ii) Online processing (2 marks)

(b) Describe the following types of human-computer interface

(i) Command line interface (3 marks)

(ii) Graphical User Interface (3 marks)

(iii) Menu-driven interface (3 marks)

(c) State the main role of each of the following network devices

(i) Bridge (1 mark)

(ii) Router (2 mark)

(iii) Modem (2 marks)

(d) Explain the difference between synchronous and asynchronous data transmission (2 marks)

3. (a) Draw a labelled diagram showing the basic components of a Central Processing Unit (4 marks)

(b) State three system buses that connect the components in (a) above (3 marks)

(c) Name four steps in the machine instruction cycle (4 marks)

(d) The following algorithm is intended to read three numbers and determine their product.Start

1. Set Count = 1

2. While Product = 1

3. While (Count <= 3) Do

4. Get a Number, N

5. Set Product = Product * N

6. Set Count = Count + 1

7. Print Product

8. Endwhile

END

14



Assume that the three numbers that are read in line 4 are 2,3 and 5

(i) Determine the output that is printed on line 7 each time the loop instructions are executed. (3 marks)

(ii) Draw a flow chart for the algorithm (6 marks)

4. (a) Given the logic circuit below:

(I) Write the logical expression for F and G (2 marks)

(II) Write TWO logic expression for H, first in terms of F and G, and then in terms of A, B, C and

D (3 marks)

(III) Given the following inputs to the logic circuit: A = TRUE, B = FALSE, C = FALSE, D = TRUE,

determine the values of F, G and H (3 marks)

(b) With aid of a suitable example in each case, state the meaning of:

(i) Input device (2 marks)

(ii) Output device (2 marks)

(iii) Input/output device (2 marks)

(c) Use binary arithmetic to evaluate

(i) 1100101 – 1010 (2 marks)

(ii) 1101011 + 1101 (2 marks)

(d) Convert the octal number 505 to a binary number (2 marks)

5. (a) Give simple definitions or explanations for the terms: - character, field, record, file, and database (5

marks)

(b) Assume you want to create a database of employees of a company, the departments they work for,

and their salaries. The tables below show sample data in the database.

A

B

D

C

H

G

F

15



EMPLOYEE

ID FNAME LNAME DEPTCODE SALCODE

1 John Doe EN S1

3 Mary Hopkins MK S2

4 Peter Miles HR S2

6 Chris Jenkins EN S3

8 Susan Jenkins MK S1

DEPARTMENT

DEPTCODE DEPARTMENT

EN Engineering

MK Marketing

HR Human Relations

SALARY

SALCODE SALARY

S1 300000

S2 250000

S3 200000

S4 100000

(I) State the number of fields and records in the EMPLOYEE table (2 marks)

(II) What do you understand by the term key database? (2 marks)

(III) What is the most appropriate key for each of the three tables (3 marks)

(IV) With the keys chosen above, if the company has another employee whose FNAME, LNAME,

DEPTCODE and SALCODE are the same as for john Doe, how can the database management

system distinguish between these two employees? (2 marks)

(V) Would it be possible to add another employee called johnny Walker whose ID is 6? Explain

your answer. (2 marks)

(VI) Explain the problem that will arise if you try to add an employee whose SALCODE is S10,

without making any other change in the database. What change would you make so that

this employee’s data can be stored in the database? (4 marks)

6. John wants to set up a company to train people on Computer Literacy. Some of the people to train only

wants to know about using machines running the Microsoft Windows Operating System, while others

only want to know about using machines running the Linux operating system. John decides to set up two

personal computer laboratories: Lab A with Microsoft Windows and Lab B with Linux computers

Answer the following questions in relation to the scenario presented above.

(a) (i) What do you understand by the terms computer literacy? (2 marks)

(ii) State FOUR functions of an operating system. (4 marks)

(b) Answer the questions in this section to explain the types of training that john should provide

his trainees

(I) List five hardware components that the trainees need to know about so that they

can understand what happens from the time they type in a document to the time a

hardcopy is produced (2 marks)

(II) Name one hardware device, and the most relevant kind of application software that

can be used to improve the typing skills of the trainees (2 marks)

16



(III) State the category of network application software that must be installed on each

computer to enable easy access to the Web? Give two examples of his category of

software (4 marks)

(IV) List four important categories of application software that should include inn the

training. For each of them, state what it is used for. Your list should NOT include

your answer in (iii) above (6 marks)

7. (a) Implementation is one of the stages of SDLC, explain the following four conversation methods that

can be used during the implementation:

(i) Parallel conversion (2 marks)

(ii) Plunge conversion (2 marks)

(iii) Pilot conversion (2 marks)

(iv) Piecemeal conversion (2 marks)

(b) Explain the following in relation to programming languages

(i) Machine Language (3 marks)

(ii) Assembly language (3 marks)

(iii) High level language (3 marks)

(c) State two disadvantages and one advantage of a machine language (3 marks)

17

1.4. JUNE 2016

18



Instructions: answer any five questions (Two hours)

1. (a) Outline THRE advantages and THREE disadvantages of email communication compared to the

conventional postal system of sending textual information (6 marks)

(b) write the following file formats in full and state two characteristics of each

(i) GIF (3 marks)

(II) jpeg (3 marks)

(c) state the difference between the following pairs of terms. Give an example in each case

(i) system software and Application software (4 marks)

(ii) Primary storage and secondary storage (4 marks)

2. (a) (i) what is an operating system? (2 marks)

(ii) Give two examples of operating system. (2 marks)

(iii) outline FOUR functions of an operating system (4 marks)

(b) (i) what do you understand by the term computer generation? (2 marks)

(ii) Complete the table below on computer generations (2 marks)

Main Technology Generation

Integrated Circuit

Vacuum Tube

Very large-scale integration (VLSI)

Transistors

(c) Briefly explain the difference between an online system and a real-time system (4 marks)

(d) Give two difference between high level languages and low-level languages (4 marks)

3. (a) State the meaning of the following terms:

(i) Human-computer interface (2 marks)

(ii) Command line interface (2 marks)

(iii) Graphical user interface (2 marks)

(b) Below is an algorithm with each line of instruction numbered on the left:

1. Begin

2. Give the price of Item, A

3. Give the number of items bought, S

4. If S < 10 then

5. Total = A*S-100

6. Else

7. Total = A*S-300

8. Print Total

9. End

19



(i) state briefly what the algorithm does (3 marks)

(ii) state the two types of control structures uses in the algorithm (2 marks)

. (iii) Determine the output if the values of A = 300 and S = 3 (3 marks)

. (iv) Represent the algorithm above using a flow chart (6 marks)

4. (a) Briefly explain the difference between data validation and data verification (2 marks)

(b) A validation rule states that only alphabetic and/or numeric characters are acceptable and that an

entry must be least five characters in length. Which two of the following data would be REJECTED by the

system?

Good is123z giving w-6856 (2 marks)

Give reasons for your answer. (2 marks)

(c) The paragraph below contains five (5) abbreviations

“Most ISP in Cameroon provide internet connectivity to major banks. Internet connectivity requires

the TCP/IP protocol, while Web use requires the HTTP protocol. Interesting how some banks prefers DSL,

some go for ADSL and some others for broadband connections.”

(i) Write the 5 highlighted abbreviations in full (5 marks)

(ii) What are the roles of the TCP/IP and HTTP protocols? (2 marks)

(d) (i) sketch each of the following logic gates, clearly labelling inputs and outputs (3 marks)

OR AND NOT

(ii) Complete the following truth table

a b ā ā OR b

1 0

0 1

1 0

0 1

5. (a) briefly explain the following as used in computer networking

(i) Bandwidth (2 marks)

(ii) Optic fibre (2 marks)

(b) Briefly describe the following as used in information systems.

(i) Management Information System (2 marks)

(ii) Expert System (2 marks)

(c) A control system is designs to regulate the temperature of a piece of equipment by detecting the

color of a light bulb and sprinkling water for 20 seconds if the color is red. Study the flow charts given

below carefully and match letters in the flowchart symbols to the corresponding items in STATEMENT

LIST.

20



(you are not expected to draw the diagram)

(d) (i) What is a project? (2 marks)

(ii) Explain the roles of PERT and Gantt charts in project management (4 marks)

6. (a) With the aid of a suitable example in each case, state the meaning of

(i) Input device (2 marks)

(ii) Output device (2 marks)

(iii) Input/output device (2 marks)

(b) (i) write in full the acronyms RAM and ROM (2 marks)

(ii) Explain briefly the term ‘volatile’ in relation to RAM and ROM (2 marks)

(c) Explain the difference between a computer’s RAM and ROM in terms of:

(i) the role of the fata and instructions held in them (2 marks)

(ii) the ability to modify the data and instructions held in the (2 marks)

(d) (i) A common mistake is to assume that 1 kilobyte (KB) is equal to 1,000 bytes, instead of 1,024 bytes.

Explain why 1KB is equal to 1,024 bytes and not 1,000 bytes (2 marks)

(iii) Determine the storage capacity of a 4GB RAM in megabytes (MB) and Kilobytes (KB) (4 marks)

Start

A

B

D

C

NO

STATEMENT LIST

1. Is light red?

2. Check color of light

Bulb

3. Sprinkle water for 20

Seconds

4. Reset color of light

bulb and wait for 10

seconds

21



7. (a) Draw and label a simplified block diagram that shows the components of an information system

(6 marks)

(b) Explain the roles of the following components of a computer system

(i) CPU (2 marks)

(ii) primary memory (2 marks)

(iii) Secondary memory (2 marks)

(c) what does the processing speed of a microprocessor measure? (2 marks)

(d) Assume the Microprocessor A has a processing speed of 300 MHz and can execute 4 instructions in

each cycle. Microprocessor B has a processing speed of 250 MHz and can execute 5 instructions in each

cycle. Which of the two microprocessors will result in faster computations? State the reason. (6 marks)

22

2. ANSWER SECTION

23

2.1. JUNE 2019

24

I. Answers to Cameroon GCE O/L Computer Science Paper 2, June 2019

Disclaimer:

Thi�s �s not an offic�al mark�ng gu�de. Thie answers g�ven here express a personal po�nt of v�ew. Pleaseuse w�th aut�on. Feel free to ontr�bute or report a problem at gamonana.wordpress.om/ontat.

1.

(a)

�. Banking:

A. Conven�eny: thanks to omputer and onl�ne bank�ng, you an from the omfort ofyour house onsult your bank aount

B. Inrease Transat�on speed: the use of omputer has made transat�ons to exeutequ�ker

ii. Managing a School Library

A. Aess to books anywhere: �t �s now poss�ble to read a book from any loat�on notonly at shool due to the use of omputer systems

B. Ease of management: the omputer makes �t eas�er and qu�ker to keep trak ofl�brary operat�ons ( lend�ng ) and searh l�brary reords.

iii. Commerce

A. No t�me l�m�tat�on. You an buy and sell goods at any t�me I.e 24hours a day 7 daysa week

B. No geograph� l�m�tat�on: You an reah ustomers any where

(b)

�. System Softwware: Thi�s �s a softwware that �s use to aess hardware and make �t usable.E.g Operat�ng System

��. Operat�ng System: An operat�ng system (OS) �s system softwware that manageshardware and softwware resoures of a omputer. Examples �nlude: W�ndows, L�nux,MaOS

25

��. Dev�e dr�vers: It �s a omputer program that ontrols a dev�e (hardware) attaahed toa omputer. E.g A Pr�nter Dev�e dr�ver ontrols the pr�nter attaahed to a omputer

�v. A ut�l�ty softwware: Also alled Appl�at�on softwware prov�des fa�l�t�es to a user toperform a spe�fic task. E.g A word proess�ng softwware.

()

Illustration 1: Example of OS

Illustration 2: Devices that need device drivers to function

26

�. Opt�al storage dev�es use laser tehnology. Examples are CD,DVD. Magnet� storagedev�es use eletromagnet� tehnology. Examples are Hard d�sk dr�ve

��. EXPLANATION: Thie surfae of hard dr�ve ons�st of onentr� �rles alled traks.Traks are further d�v�ded �nto setors.

Meanwh�le a CD ons�sts of a s�ngle sp�ral trak �rl�ng from �ns�de the CD:

Illustration 3: Difference between Optical storage and Magnetic storage

27

2.

(a) DeMorgan’s ficrst theorem states that two var�ables NORéd together �s the same as thetwo var�ables �nverted (Complement) and ANDéd,

I.e (A + B)’ = A’.B’ -----------1st theorem

wh�le the seond theorem states that two var�ables NANDéd together �s the same as thetwo terms �nverted (Complement) and ORéd.

(AB)’ = A’ + B’ ---------2nd theorem

(b)

�. P = A + B

��. Q = C.D

��. R = P + Q

= (A + B) + (C.D)

Illustration 4: Examples of logic circuits

28

HINT: An online simulator of logic gates can be found here:https://academo.org/demos/logic-gate-simulator/

()

�. Ergonom�s �s the proess of des�gn�ng produts (phone, tablet, worskspaes …) toopt�m�ze them for human use

��. Input dev�e – dev�e should �nlude a long ord for proper plaement or w�reless,should move eas�ly and be usable by leftw- and r�ght-handed users

Laptops – Use an external mouse and keyboard for extended per�ods of omputer use

Organ�zat�ons should ask employees to take regular breaks and hange your posturewhen work�ng for long per�ods of t�me.

(d) 1000000112 – 11102 I.e

10GGG0G11

111G

G011G01G1

Illustration 5: Logic circuits

-

29

3.

(a)

�. An Intranet �s a network aessed only by members w�th�n an organ�zat�on, wh�le anextranet �s network aessed by members of the organ�zat�on and outs�ders

��. Thie Internet �s a global network of onneted omputers wh�le the www �s a ollet�onof web pages aessed through the Internet. Thie Internet an be v�ewed as a road andthe www as a ar us�ng that road.

��. A browser �s used to aess webs�tes and web pages.Examples �nlude: Moz�lla F�refox.A searh eng�ne �s a softwware program that ficnds �nformat�on on the web when spe�fickeywords are entered. Examples �nlude: Google hrome, B�ng

(b)

Advantage:

It allows for Informat�on Shar�ng.

Stay �n touh w�th lassmates.

Disadvantage:

presene of Fake �nformat�on.

Add�t�on, Redued Pr�vay

Tw�ttaer, Faebook

()

�. A Computer generat�on �s harater�zed by a major tehnolog�al development thatfundamentally hanges the way a omputer operates, l�ke the use of vauum tubes,trans�stors, and the m�roproessor.

30

��. 2nd Tehnology → Trans�stors

3rd Tehnology → Integrated C�ru�t

More on omputer generat�ons here

(d)

�. Green omput�ng �s the env�ronmentally fr�endly use of omputers and the�r resoures.

Illustration 6: Computer Generations

31

https://www.webopedia.com/DidYouKnow/Hardware_Software/FiveGenerations.asp

��.

A. l�m�t�ng pr�nt�ng and reyl�ng of paper

B. reyl�ng of omputer eletron� omponents

4.

(a)

�. A predeessor task �s a task that must be ompleted or at least beg�n before anothertask an start.

Illustration 7: Example of green computing: Mail where users advices not to print if not necessary.

Illustration 8: Predecessor Task Example

32

��. Cr�t�al path: Thie r�t�al path �s the longest sequene of at�v�t�es that determ�nes theshortest poss�ble t�me to omplete a projet.

��. Slak t�me or flooat t�me �s the amount of t�me a task an be extended or postponed sothat the projet st�ll ficn�shes w�th�n the m�n�mum t�me.

(b)

�. Sl�de show appl�at�on softwware Reasons: It presents �nformat�on �n an eas�ly readablemanner

��. Projetor, Po�nter, mouse

��. Word Proess�ng softwware, PDF softwware

()

�. Thie d�ffeerene between �mpat and non-�mpat pr�nters �s that w�th �mpat pr�ntersthe �mage �s produed w�th the help of eletromehan�al �mpat dev�e but �n non-�mpat pr�nters, no mehan�al �mpat dev�e �s used. Thius �mpat pr�nters produeno�se wh�le non �mpat pr�nters work s�lently

Illustration 9: Critical Path example

33

��. Impat pr�nter: Dot-matr�x pr�nter

Non Impat Pr�nter: Laser Jet

(d)

�. Ree�ver: dev�e used to ree�ve s�gnals

��. Transm�ter: dev�e through wh�h �nformat�on passes from the sender to the ree�ver

��. A protool �s a standard set of rules that allow dev�es to ommun�ate w�th eahother.

Illustration 10: Impact Printer

Illustration 11: Non impact printer

34

5.

(a)

�. File Backup : th�s refers to mak�ng op�es of ficle to use �n the event the or�g�nal ficle �slost

��. - avo�d loss of data

- saves ost and t�me

��. 7GB to MB = 7GGGMB (h�nt: 1GB = 1GGGMB)

�v. 1G CDs of s�ze 7GGMB eah

(b)

�. DBMS: Database Management System

��. Redundany: th�s refers to the repl�at�on of the same p�ee of data �n several plaes

Cons�steny: �t states that only val�d data should be wr�ttaen to the database

Illustration 12: Components use in data transmission (communication)

35

Normal�zat�on: �t �s a tehn�que of organ�z�ng data suh that there �s l�ttale repet�t�onand that eah table should be about a spe�fic top�

()

�. Data Ver�ficat�on �s a way of ensur�ng the user types �n what he or she �ntends .�.emak�ng sure the user does not make a m�stake when �nputta�ng data.

Data Val�dat�on on the other hand �s about hek�ng �f the �nput data onforms w�ththe data requ�rements of the system to avo�d unwanted data.

��. Data Ver�ficat�on: An example �s a date hek to avo�d �nputta�ng dates that are beyondthe urrent date.

Data Val�dat�on: An example of th�s �nludes double entry of data when reat�ng apassword to prevent �norret data �nput

6.

(a)

�.

Change in the Operating System: An Open Soure Operat�ng System generally haslower ost or an even be free

Change in RAM: the omputer has a h�gher memory, wh�h means �t an exeuteprograms faster

Change in power: the UPS would allow the omputer to stay on, dur�ng no eletr��ty.Hene g�v�ng t�me for a user to save h�s work

��.

• you usually pay noth�ng or a modest fee to have the softwware

• any body an study and mod�fy the soure ode of the softwware

• you an freely d�str�bute op�es of the or�g�nal or mod�ficed vers�on

��. UPS: Un�nterrupt�ble Power Supply

36

�v.

▪ Prov�des ont�nu�ty of at�v�es

▪ Prevent�on of unwanted data loss

▪ protet dev�es from bad eletr��ty (surges)

v.

▪ Inrease hard d�sk storage

▪ Change proessors w�th those of h�gher proess�ng speed

(b)

�. Mult�task�ng alsor referred to as Mult�programm�ng �s when a omputer �s runn�ngmore than one task (program) at a t�me (l�ke runn�ng Exel and F�refox s�multaneously)wh�le Mult�proess�ng �s when a omputer �s us�ng more than one CPU at a t�me

��. A softwware update �s a m�nor hange to a softwware �ntended to ficx seur�ty bugs andorret ex�st�ng funt�onal�t�es, wh�le a softwware upgrade �s a major hangeharater�zed by new funt�onal�t�es, new graph� des�gn

��. Upload�ng �s the proess of putta�ng web pages, �mages and ficles onto a web server.Download�ng �s the proess of getta�ng web pages, �mages and ficles from a web server.

Illustration 13: Example of UPS

37

To make a ficle v�s�ble to everyone on the �nternet, you w�ll need to upload �t.Whenusers are opy�ng th�s ficle to the�r omputer, they are download�ng �t.

DISCUSSION: In Cameroon, we are fun of download�ng, let’s th�nk about upload�ng th�ngs on theweb. An example would be to reate a blog that talk of ameroon d�shes

7.

(a)

�. An algor�thm �s a set of �nstrut�ons des�gned to perform a spe�fic task.

��. |A Pseudoode �s a text based representat�on of an algor�thm

��. A floowhart �s a graph�al representat�on of an algor�thm

(b)

�. Soure ode �s ode, usually wr�ttaen �n human readable programm�ng language that �s�nputtaed �nto the omp�ler wh�le objet ode �s the output of the omp�ler.

Illustration 14: Difference between uploading and downloading

38

��. A omp�ler translates h�gh level programm�ng language �nto mah�ne language, wh�lean assembler translates assembly language �nto mah�ne language.

��. Delarat�ve programm�ng �s a programm�ng language �n wh�h you say what you wantw�thout hav�ng to say how to do �t, wh�le w�th proedural programm�ng, you have tospe�fy the deta�l steps to get the result.

()

�.

• Hardware: the phys�al omponent use to manage �nformat�on

• Softwware: omputer programs that manage �nformat�on

• Network: l�nk use to �nteronnet systems so that data an be exhanged

• Data: ollet�on of organ�zed �nformat�on

• People: the users of the system

Illustration 15: Difference between source code and object code

Illustration 16: Difference between compiler and assembler

39

• Proedures: the rules or pol��es to be respeted for �nformat�on management

��.

• every �nd�s�pl�nary at�v�ty of a student an be reorded �n the �nformat�on system

• one an v�sual�se the reords of the �nd�s�pl�nary at�v�t�es of a student for apart�ular per�od (e.g for a term or the whole shool year)

Illustration 17: Components of an Information System

40

2.2. JUNE 2018

41


1.

(a)

i. SDLC: Softw�are Development Life Cycle

ii. BIOS: Basic Input Output Softw�are

iii. PDF: Portable Document Format

iv. CPU: Central Processing Unit

(b)

i. Arithmetic logic unit (ALU), Control Unit (CU) and Memory Unit (MU) .

ii. A.L.U :- it is used in computers to perform arithmetic and logic operations .

C.U :- A control unit is a set of circuits that directs operations �ithin a computer’s processor.

M.U :- is the amount of data that can be stored.

iii. Thee fetch Decode Execute Cycle is also kno�n as the Instruction Cycle.

Fetch: Thee Program Counter (PC) points to the address of the next instruction. Theis instruction is fetched and stored inside the Instruction Register (IR)

Decode: Decode the Encoded Instruction found in the IR

Execute: Perform the Decoded Operation e.g For an addition Operation, take the values of t�o registers and actually add them Thee result generated by the operation is stored in the main memory or sent to an output device.

Thee processor goes back to the program counter to finnd the next instruction and a ne�cycle begins

42

2.

(a)

i. Network Interface Card: A Net�ork interface card is a hard�are component ( circuitboard) that connects a computer to a computer net�ork, usually a LAN (Local AreaNet�ork)

ii. Modem: Short for modulator/demodulator, a modem is a hard�are device that allo�s acomputer to send and receive information over telephone lines. It is other�ise calleddialup modem �hich is diffeerent from broadband modem

EXPLANATION: Computer information is stored digitally, �hereas information transmitteed over telephone lines is transmitteed in the form of analog �aves. When sending a signal, the device converts ("modulates") digital data to an analog audio signal, and transmits it over a telephone line. Similarly, �hen an analog signal is received, the modem converts it back ("demodulates" it) to a digital signal

Illustration 1: A Network Interface Card

Illustration 2: Examples of Modems

43

iii. Router: A router is a device that for�ards data packets along net�orks. Routers are located at gate�ays, the places �here t�o or more net�orks connect.

(b)

i. A: IF symbol

B:Input / Output Symbol

C: Start/Stop Symbol

ii. Pseudocode is a textual representation of an algorithm; for example in English, �hile floo�chart is a graphical representation of an algorithm

(c)

i. Finiteness: An algorithm should terminate aftwer a finnite number of steps

Precision (Definniteness): Each step of an algorithm must be clear and not ambiguous.

Input & Output: the algorithm must accept zero or more input and must produce at least one output.

ii. You have passed. Keep it up.

iii. Sequential construct: Lines 1,2,3 and 4

Selection construct: Line 5

Illustration 3: An example of Router

44

3.

(a)

i. difficcult to search for information;

possibility of duplicates.

Poor data security.

ii. A Database Management System (DBMS) is a softw�are used to manage data. A DBMSallo� users to create, read, update and delete data.

iii. A database refers to an integrated collection of related records. Databases are managedby specialised softw�are called Database Management Systems (DBMS)

iv. A key is a fineld (or set of finelds) that helps to uniquely identify a record.

v. Data integrity is the accuracy and completeness (consistency) of data throughout itslifecycle.

(b) User interface: Theis is the means by �hich the user and a computer system interact tocomplete tasks

(c)

i. Graphical User Interface: visual �ay of interacting �ith a computer

ii. Voice Interface: speech based �ay of interacting �ith a computer

iii. Command Line Interface: Text based �ay of interacting �ith a computer

4.

(a)

i. Storage Capacity in Bytes = 2 * 100 * 10 * 512 = 100240000 Bytes

ii. 100240000Bytes = 1024KBytes

EXPLANATION: A hard disk drive consist of a set of platteers. Each platteer is made up of concentric circles called Tracks. A sector is a portion of a track. It is the smallest unit of storage.

45

(b)

i. faster speed and less finle loading time

ii. avoid the loss of data by keeping data in a secondary (another) location

iii. prevent the atteack of virus, protect your computer.

(c)

46

i. Read Only Memory:this is a storage location that keeps unmodifinable data.

ii. Random Access Memory: this is main memory that stores modifinable data

iii. Hard disk: this is computer memory that stores data on a long term basis.

(d)

i. Cybercrime: is a crime that involves a computer and a net�ork

ii. Spamming : floooding of someone’s e-mail �ith un�anted emails

Phishing: fraudulent atteempt to obtain someone’s personal information

5.

(a)

i. Confindentiality: ensures that sensitive information are accessed only by an authorized person

ii. Softw�are damage: anything that can cause harm to softw�are.

iii. Unauthorized access: Theis is �hen someone gains access to a system using someone else's account or other methods. For example, if someone kept guessing a pass�ord or username for an account that �as not theirs until they gained access, it is considered unauthorized access.

iv. Unauthorized Use: this is the use of a system �ithout the o�ner’s consent

(b) Measures to check Confindentiality: Use of username/pass�ord; data encryption

Measures to check Unauthorized access: install finre�all, install antivirus (or spy�are)

(c)

i. EXPLANATION :

A hexadecimal number is a base-16 number and uses sixteen distinct symbols : from 0 to 15. An octal number or oct for short is a base-8 number and uses the digits 0 to 7. Octal numerals can be made from binary numerals by grouping consecutive binary digits into groups of three (starting from the right).

Ho� to convert?

Step 1: Find the equivalent binary number for each digit in the given hexadecimal number. Add 0’s to the leftw if any of the binary equivalent is shorter than 4 bits

Step 2: Separate the binary digits into groups, each containing 3 bits or digits from right to leftw. Add 0s to the leftw, if the last group contains less than 3 bits.

Step 3: Find the octal equivalent for each binary group.

Note that for a hexadecimal number A is equivalent to 10, B to 11, C to 12, … E to 15

47

Source:

SOLUTION

to convert DC to octal, �e �ill apply our three step method above

◦ step 1: DC16 → 1101 11002

◦ step 2: 1101 11002 → 0110011 1002. (the last zero has been added to have groups of 3 digitseach

◦ Step 3: 3348

ii. 10001101012 = (1*27) +(0*26) +(0*25) +(1*24) +(1*23) +(1*22) +(0*21) +(1*20)

= 128 + 0 + 0 + 16 + 8 + 4 + 0 + 1

= 15710

Check the correctness of this ans�er here

6.

(a)

i. Analysis → Design → Implementation → User Support

ii. Analysis: Data Collection, Data Interpretation, �rite the softw�are requirements

Design: Implementation of process (activity) diagrams (using floo�chart), dra�ing ofscreen layouts

(b)

i. Systems Analyst: they do Data Collection and analysis. Theey are also involved indesigning the system. Theey produce the System’s Requirement.

ii. Programmer: they implement the system. Theey �rite softw�are code

(c)

i. ��: World Wide Web

ii. Thee Internet is a global net�ork of connected computers �hile �� is a collection of�eb pages accessed through the Internet. Thee Internet can be vie�ed as a road and�� as a car using that road.

iii. A blog is a �ebsite , typically one run by an individual or small group, that is �ritteenin an informal or conversational style. An Internet Relay Chat (IRC) is a system forchatteing that involves a set of commands and a client/server softw�are. Some of thecommands include: “/help” �hich is used to bring up a list of all the commands or thehelp �indo�.

(d)

48

https://www.rapidtables.com/convert/number/binary-to-decimal.html

i. A social net�ork is a �ebsite or virtual community that allo�s people �ith similarinterests to come together, share and comment on information, photos and videos.

ii. Facebook, LinkedIn, T�itteer

iii. advantage:

It allo�s for Information Sharing.

Stay in touch �ith friends and family that are distant apart.

Disadvantage:

presence of Fake information.

Addiction, Reduced Privacy

7.

(a)

i. An operating system (OS) is system softw�are that manages hard�are and softw�are resources of a computer. Examples include: Windo�s, Linux, MacOS

ii. Memory Management,

File management,

Booting of the computer,

Process Management,

Providing Interface (Command Line Interface and Graphical User Interface).EXPLANATION: A comprehensive list of the functions of the Operating System canbe found here. Look at the section “Characteristics of Operating System”

(b)

i. high level langage is machine independent �hile lo� level langage is machinedependent;

high level langage is close to human langage �hile lo� level is not close to humanlanguage.

ii. Lo� level language: x86 assembly

High Level Language: python

(c)

i. An Interpreter translates a program one statement at a time to produce machine code.It does not generate an intermediate object code. Programming languages like Python,PHP, use Interpreters

49

https://www.tutorialspoint.com/computer_fundamentals/computer_operating_system

ii. A compiler translates a program as a �hole into machine code. It generates anintermediate object code before producing the machine code. Programming languageslike C, C++, Java use compilers

(d)

i. P = X + Y

ii. Q = Z + W

iii. R = P + Q

50

2.3. JUNE 2017

51


Disclaimer:

Thi�s �s not an offic�al mark�ng gu�de. Thie answers g�ven here express a personal po�nt of v�ew. Please ontr�bute or report a problem at gamonana.wordpress.om/ontat

1.

(a)

�. Data Encryption : Thi�s �s a seur�ty method by wh�h data �s onverted to a formwhere you need a seret key to aess or read �t. Thi�s seret key �s formally alledEnrypt�on key. Thie onverted text �s alled �phertext wh�le the or�g�nal text �spla�ntext

��. Backup : th�s refers to mak�ng op�es of data to use �n the event the or�g�nal data �s lost

��. Firewall : th�s �s a seur�ty system that fillters �nom�ng and outgo�ng traffic(messages)based on defilned sets of rules. It �s s�m�lar to a phys�al barr�er that fillters aess �n andout of the ompound.

(b) Data integrity �s the auray and ompleteness (ons�steny) of data throughout �tsl�feyle. Data �ntegr�ty an be ma�nta�ned through the use of var�ous error-hek�ngmethods and val�dat�on proedures.

() Data Verificcation �s a way of ensur�ng the user types �n what he or she �ntends .�.e mak�ngsure the user does not make a m�stake when �nputti�ng data. An example of th�s �nludesdouble entry of data when reat�ng a password to prevent �norret data �nput

Data Validation on the other hand �s about hek�ng �f the �nput data onforms w�th thedata requ�rements of the system to avo�d unwanted data. An example �s a date hek toavo�d �nputti�ng dates that are beyond the urrent date.

(d)

�. Computer Simulation: th�s refers to the use of a omputer to �m�tate a system usuallya real-world system. Thie �m�tat�on proess �s based on a sets of mathemat�alequat�ons (mathemat�al model). Thie purpose of s�mulat�on �s to pred�t the results ofsometh�ng

��. Advantages:

Avoid disturbing real world systems: W�th Computer S�mulat�on, �t �s poss�ble to test the behav�or of someth�ng. We an model a system lose enough to real world. Exper�ments are done on the model w�thout d�sturb�ng the real world system.

52

Help Students: Teahers an do s�mulat�on of systems and expla�n to students. Students an get an �dea of any system eas�ly be see�ng a s�mulat�on

D�sadvantages:

Expensive : Computer s�mulat�on �s expens�ve beause �t requ�res a group of h�ghly qual�filed �nd�v�duals bu�ld the s�mulat�on model

Computer limitation : Complex s�mulat�on �nvolves a omputer w�th h�gher memory and proessor speed. Thi�s �s another drawbak of s�mulat�on.

2.

(a)

�. Bath proess�ng �s a method of runn�ng data jobs periodically w�th little or no userinteraction. Bath jobs are olleted �n bulk rather than d�ret �nput from user and areproessed at a later t�me. Example :Shedul�ng the automat� payment of employeesevery month

��. Onl�ne proess�ng �s a method of runn�ng data jobs continuously as they are �nputtied.Thie �nputtied data �s d�retly proessed and outputtied. Example: the bank ATM �s anexample of onl�ne proess�ng as data �s �mmed�ately proessed and outputtied asustomers send �nput to the mah�ne.

(b)

�. A command-line interface �s a text based way of �nterat�ng w�th a omputer programwhere the user �ssues ommands to the program �n the form of suess�ve l�nes of textalled ommand l�nes and ree�ves responses also �n the form of suess�ve l�nes of

Illustration 1: A bank ATM

53

text. Thi�s type of �nterfae �s not �deal for nov�e users as you must remember therange of d�ffeerent ommands

��. A GUI �s a v�sual way of �nterat�ng w�th a omputer program us�ng �tems suh asW�ndows, Ions, Menus and Po�nters (WIMP)

Illustration 2: A command line interface

54

��. Menu Driven Interface : th�s �s an �nterfae that ons�st of a ser�es of menus and sub-menus wh�h the user aesses by press�ng buttions, ofteen on a touh-sreen dev�e. Aommon example �s the ATM

Illustration 3: A GUI

55

()

�. NOT YET ANSWERED

(d) Synchronous data transmission �s a data transfer method �n wh�h data bloks areont�nuously and ons�stently be�ng transfer. Examples �nlude : telephon� onversat�ons,v�deo onferen�ng

Asynchronous data transmission �s a data transfer method �n wh�h data �s transm�ttiedd�sont�nuously and a start and stop be�ng must be�ng �nsereted �n eah data blok to�nform the ree�ver where �t beg�ns and ends. Examples �nlude : ema�ls

3.

Illustration 4: Example of Menu driven Interface

56

(a) EXPLANATION: C.P.U :- Thie CPU �s the heart and bra�n of a omputer .Thee threecomponents of the CPU:

▪ (A.L.U) Ar�thmet� log� un�t .

▪ (C.U) Control Un�t .

▪ (M.U) Memory Un�t .

A.L.U :- An ar�thmet� log� un�t �s a d�g�tal �ru�t used �n omputers to performar�thmet� and log� operat�on .

C.U :- A ontrol un�t �s �ru�try that d�rets operat�ons w�th�n a omputer’s proessor.

M.U :- Memory un�t �s the amount of data that an be stored.

(b) Address Bus: It �s a group of w�res wh�h arr�es address only.Address bus �sun�d�ret�onal beause data floow �n one d�ret�on, from m�roproessor to memory or fromm�roproessor to Input/output dev�es

Data Bus:It �s a group of w�res wh�h arr�es Data only.Data bus �s b�d�ret�onal beausedata floow �n both d�ret�ons, from m�roproessor to memory or Input/Output dev�es andfrom memory or Input/Output dev�es to m�roproessor

Control Bus: It �s a group of w�res, wh�h �s used to generate t�m�ng and ontrol s�gnals

Illustration 5: Basic Components of a CPU

57

() the mah�ne �nstrut�on yle ons�sts of : Feth the �nstrut�on, deode the �nstrut�on,Exeute and Store result.

(d)

�. for N = 2, Produt = 2

for N = 3, Produt = 6

for N = 5, Produt = 30

��.

Illustration 6: Types of buses in a Computer

58

EXPLANATION: Thie de�s�on symbol always appear at the end of a wh�le loop. If theond�t�on �s true, the arrows goes bak to the start of the loop otherw�se the loop �sterm�nated

the �nput/output symbol �s .

but beause my softeware does not have �t I have used

4.

(a)

�. F represents the result of an AND GATE: A.B

G represents the result of an OR GATE: C+D

��. H: F + G

H:(A.B) + (C+D)

��. F: FALSE

G: TRUE

H: TRUE

(b)

�. An input device �s a hardware dev�e that sends data to a omputer allow�ng you to�nterat w�th �t. Examples �nlude : keyboard, mouse, sanner, m�rophone, bar odereader.

��. An output device �s a hardware dev�e that d�splays (or ree�ves) data from aomputer. Examples �nlude: Pr�nters, Mon�tors, Projetors

��. An input / output device �s a dev�e that an both send data to a omputer and d�splay(or ree�ve) data from a omputer. Example: A USB Dr�ve sends data to a omputerand d�splays (or ree�ves) data from a omputer

()

�. 111001101 (represents 101 �n base ten) - 010011010 (represents 10 �n base ten) = 110111011(represents 91 �n base ten)

EXPLANATION: w�th b�nary subtrat�on 0 – 1 = 1 and 1 �s borrowed from the nexts�gn�filant b�t. Note that w�th suess�ve borrows, the values are deduted aord�ngly.

60

Eg 1: ons�der 1001 – 101 . �n the th�rd substrat�on (I.e 0 – 1) 1 �s borrowed andappended to zero wh�h now beomes 10 – 1 (I.e 2 -1) wh�h �s equal to 1. Thie fourthsubstrat�on beomes 0 – 0 = 0. the filnal result g�ves 100.

Eg 2: Cons�der 1000 – 111 = 0001. In the filrst substrat�on (I.e 0 - 1) 1 �s borrowed fromthe 1 at the fourth pos�t�on. Thi�s 1 �s appended to the zero at the th�rd pos�t�onbeom�ng 10. 1 aga�n �s deduted here so that what �s lefte �s 1 and the seond pos�t�onbeomes 10. 1 �s aga�n deduted here so that what �s lefte �s 1 and we have a 10 at thefilrst pos�t�on. We now have 10 – 1 wh�h g�ves 1. Thie next substrat�ons are 111 – 111wh�h g�ves 000. hene the result 0001. V�s�t th�s to learn more about B�narysubtrat�on and here to have for b�nary to de�mal onvers�ons

��. 111011011 (represents 107) + 001011 01 (represents 13) = 111111000 represents 120 notethat w�th b�nary add�t�on 1 + 1 = 0 and 1 �s arr�ed. Also 1+1+1=1 and 1 �s arr�ed

(d) 5058 = 101100011012 . EXPLANATION: otal means base 8 notat�on. Thiere are only 8symbols : from 0 to 7. the algor�thm to onvert from otal to b�nary �s :

▪ onvert eah d�g�t �n the otal number �nto �ts 3 d�g�t b�nary equ�valent.

▪ Thie result �s the b�nary number

5.

(a) Character : �t ons�st of 8 b�ts. 8 b�ts an also be alled a byte. A b�t �s the smallest un�t ofdata representat�on. Thie value of a b�t �s e�ther 0 or 1.

Field : a fileld ons�st of a group of haraters. A fileld �s used to desr�e an ent�ty (objet,person, plae or event). E.g the ent�ty person may have as fileld: name

Record : a Reord �s a ollet�on of filelds, w�th eah fileld desr�b�ng the ent�ty. E.g theent�ty person may have a reord ons�st�ng of the filelds : name, age and sex

File: A group of related reords make up a fille. E.g the Person’s fille ons�st�ng of a ser�es ofreords of persons

Database : �t refers to an �ntegrated ollet�on of related reords or filles. Databases aremanaged by spe�al�sed softeware alled Database Management Systems (DBMS)

EXPLANATION: Thiese �tems from the Hierachy of data.

(b)

�. 5 filelds and 5 reords

��. key: �t �s the fileld that enables to un�quely �dent�fy a reord

��. EMPLOYEE → ID; DEPARTMENT → DEPTCODE; SALARY → SALCODE

61

https://www.math-only-math.com/binary-subtraction.html

https://www.rapidtables.com/convert/number/binary-to-decimal.html

�v. by us�ng the ID fileld wh�h w�ll be d�ffeerent for both employees

v. NO. Beause the entry �n the ID fileld shoud be un�que. Thie ID 6 has already be�ng used

v�. some of the employee’s orrespond�ng reord m�ght not filgure �n the DEPARTMENTand SALARY tables. Add the orrespond�ng reord to the DEPARTMENT andSALARY tables

6.

(a)

�. Computer literacy �s defilned as the knowledge and ab�l�ty to ut�l�ze omputers andrelated tehnology effic�ently

��. Boot�ng, Memory management, D�sk management, Prov�d�ng Interfae.

(b)

�. keyboard, mouse, mon�tor, pr�nter

��. Hardware dev�e: keyboard

softeware: A Word Proess�ng softeware

��. Internet browser: Moz�lla F�refox, Google Chrome

�v. Spreadsheet Softeware : A tool used to reate lettiers, word sheets

Desktop Publ�sh�ng Softeware: A tool used to reate �llustrat�ve worksheets, banners

Database Softeware: A tool used to store data l�ke text �nformat�on

Presentat�on Softeware: used to reate mult�med�a apps

7.

(a)

EXPLANATION: SDLC stands for Softeware Development L�fe Cyle. It represents allthe phases �nvolved �n the development of a softeware.

�. Parallel conversion �s an �mplementat�on tehn�que �n wh�h an ex�st�ng system runs�n parallel w�th the new system, to ver�fy that both produe �dent�al results and thusensure that the new system an orretly takeover the ex�st�ng system.

��. Plunge conversion �s an �mplementat�on tehn�que �n wh�h there �s an abrupt hangefrom the old system to the new system at a predefilned t�me. Thi�s method fores theusers to make the new system work s�ne they have no other method to fall bak on.

��. Pilot conversion �s an �mplementat�on tehn�que �n wh�h a work�ng vers�on of thesystem �s �mplemented �n one part of the organ�zat�on, suh as a s�ngle department. Asthe system �s be�ng used, hanges an be made to �mproved �t. When the system �s

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deemed omplete, �t �s �nstalled throughout the organ�zat�on, e�ther at one (d�retonvers�on) or gradually (phased or p�ee meal onvers�on). P�lot onvers�ons are onlyposs�ble �n organ�zat�ons that have d�srete set�ons or branhes.

�v. Piecemeal conversion otherw�se alled Phased onvers�on �s an �mplementat�ontehn�que �n wh�h the new system �s �ntrodued gradually. It an be used when �t �snot poss�ble to �nstall a new system throughout an organ�sat�on all at one.

(b)

�. Machine Language �s a programm�ng language ons�st�ng of b�nary or hexade�mal�nstrut�ons wh�h a proessor an respond to d�retly. Suh programm�ng langagesneed no translat�ons to be understood by the proessor. Mah�ne languages areproessor dependent and thus not portable (�e the ode wr�ttien for one proessor annot be used on a d�ffeerent proessor). Mah�ne langages are d�fficult to read, wr�te andma�nta�n

��. An assembly language, also reffeered to as ASM, �s a low-level programm�ng language�n wh�h there �s a very strong orrespondene between the program's statements andthe �nstrut�ons wh�h the proessor understands. Assembly langages are translated�nto mah�ne langage us�ng an assembler Assembly langages are also d�fficult toread,wr�te and ma�nta�n. Thiey are not very portable.

��. High level language �s a programm�ng langage lose to human langage, �s mah�ne�ndependent and thus portable. Thiey are eas�er to read, wr�te and ma�nta�n. Thiey aretranslated �nto mah�ne langage us�ng a omp�ler or �nterpreter

() two d�sadvantages of Mah�ne Language: d�fficult to read, wr�te; not portable

advantage: qu�kly �nterpreted by the Proessor

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2.4. JUNE 2016

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Disclaimer:

Thi�s �s not an offic��al mark�ng gu�de. Thie answers g�ven here express a personal po�nt of v�ew. Pleaseuse w�th �aut�on. Feel free to �ontr�bute or report a problem at gamonana.wordpress.�om/�onta�t

1.

(a) 03 advantages of ema�l �ommun��at�on: �t �s fast;�t �s �nexpens�ve; �t �s permanent - you �ankeep a re�ord of messages and repl�es, �n�lud�ng deta�ls of when a message was re�e�ved

03 d�sadvantages of ema�l �ommun��at�on: a��ess�ble to others that �an read your ema�lsw�thout you know�ng; presen�e of spam that �an floood your ma�l box w�th undes�rablema�l ; presen�e of v�rus that �an damage your �omputer.

(b)

�. GIF: Graph�� Inter�hange Format

characteristics: g�f uses loss-less �ompress�on algor�thm mean�ng �t does not getblurry; g�f �an be an�mated; �t d�splays a max�mum of 256 �olours. Thi�s makes �t a poorformat for photograph�� mages

ii. JPEG: Jo�nt Photograph�� Experts Group

characteristics: jpeg uses a lossy �ompress�on algor�thm; �t �s �apable of d�splay�ng am�ll�on of �olors that makes �t su�table for photograph�� mages; �t �annot be an�mated

(�)

�. System softwware �s softwware used to operate �omputer hardware. It prov�des platformto run appl��at�on softwware. E.g Operat�ng System. Application softwware �s softwwarethat prov�des fa��l�t�es to user to perform spe��fic� task. E.g word pro�essor softwware

��. Primary storage otherw�se �alled ma�n memory �s memory that �an be d�re�tlya��esed by CPU. Pr�mary storage �s volat�le �n nature. Examples �n�lude RAM, Ca�he

Secondary storage �annot be d�re�tly a��essed by the CPU. It �s used to store data on along term bas�s . Examples �n�lude Hard D�sk dr�ves, USB dr�ves

2.

(a)

�. An operating system (OS) �s system softwware that manages hardware and softwwareresour�es of a �omputer.

��. Ubuntu, CentOS, W�ndows 7

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��. Memory Management, F�le management, Boot�ng of the �omputer,Pro�ess Management, Prov�d�ng Interfa�e (Command L�ne Interfa�e and Graph��alUser Interfa�e)

(b)

�. A Computer generation �s �hara�ter�zed by a major te�hnolog��al development thatfundamentally �hanges the way a �omputer operates, l�ke the use of va�uum tubes,trans�stors, and the m��ropro�essor.

��.

Main Technology Generation

Integrated C�r�u�t 3rd

Va�uum Tube 1st

Very large-s�ale Integrat�on (VLSI) 4th

Trans�stors 2nd

(�) A real time system �s a system wh��h prov�des �mmed�ate pro�ess�ng and response to thedata be�ng �nputteed e.g an A�rl�ne Reservat�on system

An online system �s a system �onne�ted to the Internet. Su�h system may not�mmed�ately pro�ess and g�ve a response to an �nputteed data. E,g brows�ng a webpage

(d) h�gh level langage �s ma�h�ne �ndependent wh�le low level langage �s ma�h�ne dependent

h�gh level langage �s �lose to human langage wh�le low level �s not �lose to humanlanguage

3.

(a)

�. Human–computer Interface (HCI) �s a ficeld of study that fo�uses on the des�gn anduse of �omputer te�hnology, and �n part��ular the �ntera�t�on between humans (users)and �omputers

��. A command-line interface �s a text based way of �ntera�t�ng w�th a �omputer wherethe user �ssues �ommands �n the form of su��ess�ve l�nes of text �alled �ommand l�nesand re�e�ves responses also �n the form of su��ess�ve l�nes of text.

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Illustration 1: A command line interface

��. A GUI �s a v�sual way of �ntera�t�ng w�th a �omputer program us�ng �tems su�h asW�ndows, I�ons, Menus and Po�nters (WIMP)

Illustration 2: An example of GUI

(b)

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�. the algor�thm mult�pl�es the pr��e of an �tem w�th the number of �tems

�f the number of �tems �s less than 10, a d�s�ount of 100 �s appl�ed to the total pr��e

�f the number of �tems �s greater than or equal to 10, a d�s�ount of 300 �s appl�ed to thetotal pr��e

��. Sequent�al and Sele�t�on Control Stru�tures

��. Total = 800

�v.

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Thie �nput/output symbol �s .

but be�ause my softwware does not have �t I have used

4.

(a) Data Validation �s about �he�k�ng �f the �nput data �onforms w�th the data requ�rements of the system to avo�d unwanted data. An example �s a date �he�k to avo�d �nputte�ng dates that are beyond the �urrent date.

Data Verificcation �s a way of ensur�ng the user types �n what he or she �ntends .�.e mak�ng sure the user does not make a m�stake when �nputte�ng data. An example of th�s �n�ludes double entry of data when �reat�ng a password to prevent �n�orre�t data �nput

(b) Good:�s less than 5 �hara�ters �n length

w-6856: has a non alphabet�� or numer�� hara�ter wh��h �s -

(�)

�. TCP/IP: Transm�ss�on Control Proto�ol/ Internet Proto�ol

HTTP: HyperText Transfer Proto�ol

DSL: D�g�tal Subs�r�ber L�ne

ADSL: Asymmetr�� D�g�tal Subs�r�ber L�ne

��. HTTP �s used to transm�t webs�te �nformat�on (text,graph��, sound, aud�o…) a�ross the Internet

TCP/IP transm�ss�on of data (web pages, ema�l, ficles …) a�ross the Internet

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(d)

�. EXPLANATION : �hoose the OR, AND and NOT gates

��.

A B Not A (NOT A) or B

1 0 0 0

0 1 1 1

1 0 0 0

0 1 1 1

5.

(a)

�. Bandwidth: the amount of data that �an be transm�tteed �n a ficxed amount of t�me. It �sexpressed as bytes per se�ond

��. Optic fic7re: A te�hnology that uses glass threads (ficbers) to transm�t data

(b)

�. Management Information System: refers to an �nformat�on system that �s used �nde��s�on-mak�ng and prov�de tools for managers to �oord�nate, evaluate and effic��entlymanage an organ�zat�on

��. an expert system �s a �omputer system that emulates the de��s�on-mak�ng ab�l�ty of a human expert

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(�) A:2

B: 1

C:3

D:4

(d)

�. a project �s an temporary endeavour w�th a deficned start and end date.

��. Thiese two proje�t management tools help:

to �dent�fy tasks

to est�mate proje�t durat�on

to show the �nterdependen�y of tasks

PERT (Program Evaluation Review Technique) charts are generally used before aproje�t beg�ns to plan and determ�ne the durat�on of ea�h task. Thiey are used for largeand �omplex proje�ts. Gantt charts are used wh�le a proje�t �s happen�ng to breakproje�ts �nto smaller tasks and h�ghl�ght s�hedul�ng �onstra�nts. Thiey are used forsmall proje�ts.

6.

(a)

�. An input device �s a hardware dev��e that sends data to a �omputer allow�ng you to�ntera�t w�th �t. Examples �n�lude : keyboard, mouse, s�anner, m��rophone, bar �odereader.

��. An output device �s a hardware dev��e that d�splays (or re�e�ves) data from a�omputer. Examples �n�lude: Pr�nters, Mon�tors, Proje�tors

��. An input / output device �s a dev��e that �an both send data to a �omputer and d�splay(or re�e�ve) data from a �omputer. Example: A USB Dr�ve sends data to a �omputerand d�splays (or re�e�ves) data from a �omputer

(b)

�. RAM: Random A��ess Memory

ROM: Read Only Memory

��. RAM �s volat�le, wh�le ROM �s not

(�)

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�. Thie data stored �n ROM �s used pr�mar�ly �n the startup pro�ess of a �omputer, whereas data �n RAM �s used aftwer the Operat�ng System has been loaded

��. RAM data �an be mod�fy, ROM data �s not mod�ficable

(d)

�. 1KB = 1,024 bytes be�ause 1KB �s 2 10 bytes

��. 4GB = 4000MB = 400000000KB

7.

(a) EXPLANATION: there are 6 �omponents of an Informat�on System: People, Pro�edures,Hardware, Softwware, Data, Network

(b)

�. CPU: �t �s used to pro�ess data

��. Primary Memory: th�s �s ma�n memory. It stores data d�re�tly a��ess�ble by the CPU.Eg. RAM

Illustration 3: Components of an Information System

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��. Secondary Memory: th�s �s memory that holds data on a long term bas�s. It stores datathat �s not d�re�tly a��ess�ble by the CPU e.g Hard d�sk dr�ve

(�) �t measures the performan�e of a CPU. Thie un�t of measurement �s �alled Hertz

(d) t�me = Number of �nstru�t�ons / frequen�y

for m��ropro�essor A, t�me = 4/300 = 0.01s

for m��ropro�essor B, t�me = 5/250 = 0.02s

m��ropro�essor A �s faster s�n�e �t exe�utes �ts �nstru�t�on �n fewer t�me

EXPLANATION: truly speak�ng time = Num7er of instructions * (1 / frequency)

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SOME TIPS WHEN WRITING THE EXAM 1. To get familiar with the type of questions asked, get to solve as many past questions

as possible;

2. You must not necessarily solve all GCE past questions for you to succeed. A couple of

past questions for 3 to 5 years is enough;

3. Start with the easy questions first, it gives you motivation. Once you are done with

the easy questions you can go tackle the difficult one.

4. When revising for your exam, do not seek to cram but to understand your notes.

Understand in your words would stick better into your brain than trying to memorize

the notes of your teacher, word for word;

5. Pray before you start writing your exam. God always guide his Children.

GAMO NANA,

Tel: 697518768.

Email: [email protected]

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CAMEROON PAST GCE ORDINARY LEVEL COMPUTER …...May 05, 2019 · Name any three hardware devices...

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Transcript of CAMEROON PAST GCE ORDINARY LEVEL COMPUTER …...May 05, 2019 · Name any three hardware devices...